Formation of Acetylene in the Reaction of Methane with Iron Carbide Cluster Anions FeC3 − under High-Temperature Conditions

Coordination-induced bond weakening in NiC3: An experimental and theoretical investigation

Mass-selected photoelectron velocity-map imaging spectroscopy in conjunction with the density functional theory calculations was employed to investigate the geometrical and chemical bonding properties of NiC3-/0. Both the photoelectron spectrum and photoelectron angular distribution were measured from the spectra, yielding useful geometrical and electronic information about NiC3-/0. The complementary theoretical calculations suggest that the linear and fan-like structures were both populated experimentally in the cluster beam. Further comparative study on the synergistic donor-acceptor interactions in both isomers revealed the side-on coordination-induced bond weakening in the fan-like isomer as compared to the linear isomer. These findings will shed light on the structure-dependent reactivity of transition metal carbides.

Photoelectron velocity-map imaging spectroscopy of nickel carbide: Examination of the low-lying electronic states

The photoelectron detachment of nickel carbide anion has been characterized using the photoelectron velocity-map imaging spectroscopy, allowing for a precise assignment of the electron affinity, vibrational frequencies, energy spacing and...

Subsurface-Carbon-Induced Local Charge of Copper for an On-Surface Displacement Reaction

Transition-metal carbides have sparked unprecedented enthusiasm as high-performance catalysts in recent years. Still, the catalytic properties of copper carbide remain unexplored. By introducing subsurface carbon to Cu(111), a displacement reaction of a proton in a carboxyl acid group with a single Cu atom is demonstrated at the atomic scale and room temperature. Its occurrence is attributed to the C-doping-induced local charge of surface Cu atoms (up to +0.30 e/atom), which accelerates the rate of on-surface deprotonation via reduction of the corresponding energy barrier, thus enabling the instant displacement of a proton with a Cu atom when the molecules adsorb on the surface. This well-defined and robust Cu^δ+ surface based on subsurface-carbon doping offers a novel catalytic platform for on-surface synthesis.

Catalytic Co-Conversion of CH4 and CO2 Mediated by Rhodium-Titanium Oxide Anions RhTiO2. Angew Chem Int Ed Engl 2021;60:13788-13792. [PMID: 33890352 PMCID: PMC8251526 DOI: 10.1002/anie.202103808]

Catalytic co‐conversion of methane with carbon dioxide to produce syngas (2 H₂+2 CO) involves complicated elementary steps and almost all the elementary reactions are performed at the same high temperature conditions in practical thermocatalysis. Here, we demonstrate by mass spectrometric experiments that RhTiO₂⁻ promotes the co‐conversion of CH₄ and CO₂ to free 2 H₂+CO and an adsorbed CO (CO_ads) at room temperature; the only elementary step that requires the input of external energy is desorption of CO_ads from the RhTiO₂CO⁻ to reform RhTiO₂⁻. This study not only identifies a promising active species for dry (CO₂) reforming of methane to syngas, but also emphasizes the importance of temperature control over elementary steps in practical catalysis, which may significantly alleviate the carbon deposition originating from the pyrolysis of methane.

Coupling of Methane and Carbon Dioxide Mediated by Diatomic Copper Boride Cations

The use of CH₄ and CO₂ to produce value-added chemicals via direct C-C coupling is a challenging chemistry problem because of the inertness of these two molecules. Herein, mass spectrometric experiments and high-level quantum-chemical calculations have identified the first diatomic species (CuB⁺ ) that can couple CH₄ with CO₂ under thermal collision conditions to produce ketene (H₂ C=C=O), an important intermediate in synthetic chemistry. The order to feed the reactants (CH₄ and CO₂ ) is important and CH₄ should be firstly fed to produce the C₂ product. Molecular-level mechanisms including control of product selectivity have been revealed for coupling of CH₄ with CO₂ under mild conditions.